1. Field of the Invention
The present invention relates to an epoxy sealer/healer for sealing and strengthening cracked concrete.
2. Description of the Related Art
Concrete is used to make many structures, including bridges, roadways, tunnels, runways, parking ramps and decks, parapet walls, precast beams, columns, curbing, retaining walls and pavers. These structures commonly develop cracks upon exposure to the environment and to man-made activities. Thus, there is a widespread need for a composition for sealing and repairing cracked concrete structures.
Numerous compositions for sealing cracked concrete are known. One example is methacrylate-based formulations. These compositions suffer, however, from the disadvantages of being brittle, not useable under wet conditions, and generally slow curing. Another example is poly-siloxane-based resin formulations. These are not useable to seal visible cracks but, rather, are used as penetrants.
Epoxy-based compositions for sealing cracks in concrete are also known. A commercially available product called Denepox 40 is marketed by DeNeef America Inc. Denepox 40 is said to be a low viscosity, two-component epoxy resin system which can be applied to concrete cracks by pressure injection or by gravity feeding. Denepox 40 is a 100% solids resin said to be insensitive to the presence of water and useful for application to damp concrete surfaces. Denepox 40 is advertised as having a pot life of 80 minutes at 77.degree. F., and a mixing viscosity of 40 centipoise at that temperature.
Versafill 60A/60B is a product made by Henkel Corporation and is a two-component epoxy system designed to penetrate and bond cracks in concrete structures. The material can either be injected or applied through gravity feed. Versafill 60A/60B is said to penetrate deeply into a crack (down to 4 thousandths of an inch in width), have little odor, and contain no solvents. The mixed two-component epoxy system is advertised as having a viscosity of 3.0-5.0 poise and a gel time of about 60 minutes.
Dural 335 is marketed by Tamms Industries and is characterized as a two-component, 100% solids, low viscosity epoxy resin for sealing concrete cracks and surfaces. Dural 335 is said to flow readily for deep penetration into cracks; the mixed formulation purportedly having a viscosity of 83 centipoise at 75.degree. F., and a pot life of 40-50 min. Although the cured formulation is said to be moisture insensitive, surfaces and cracks must be completely dry before application of Dural 335 to obtain maximum penetration.
While epoxy-based formulations for sealing cracked concrete are known, they suffer from several disadvantages. Epoxy-based formulations usually have a high viscosity which, therefore, leads to poor crack penetration. Epoxy-based formulations also tend to have long tack-free times and some cannot bond to concrete and/or cure in the presence of water moisture. While some of those disadvantages have been overcome by products currently available, none of the products overcomes all of the disadvantages. The present invention provides a formulation which overcomes all of the aforementioned disadvantages.